// Copyright (C) 2002-2012 Nikolaus Gebhardt
// This file is part of the "Irrlicht Engine".
// For conditions of distribution and use, see copyright notice in irrlicht.h

#include "CMemoryFile.h"
#include "irrString.h"

namespace irr
{
namespace io
{


CMemoryReadFile::CMemoryReadFile(const void* memory, long len, const io::path& fileName, bool d)
: Buffer(memory), Len(len), Pos(0), Filename(fileName), deleteMemoryWhenDropped(d)
{
	#ifdef _DEBUG
	setDebugName("CMemoryReadFile");
	#endif
}


CMemoryReadFile::~CMemoryReadFile()
{
	if (deleteMemoryWhenDropped)
		delete [] (c8*)Buffer;
}


//! returns how much was read
size_t CMemoryReadFile::read(void* buffer, size_t sizeToRead)
{
	long amount = static_cast<long>(sizeToRead);
	if (Pos + amount > Len)
		amount -= Pos + amount - Len;

	if (amount <= 0)
		return 0;

	c8* p = (c8*)Buffer;
	memcpy(buffer, p + Pos, amount);

	Pos += amount;

	return static_cast<size_t>(amount);
}

//! changes position in file, returns true if successful
//! if relativeMovement==true, the pos is changed relative to current pos,
//! otherwise from begin of file
bool CMemoryReadFile::seek(long finalPos, bool relativeMovement)
{
	if (relativeMovement)
	{
		if (Pos + finalPos > Len)
			return false;

		Pos += finalPos;
	}
	else
	{
		if (finalPos > Len)
			return false;

		Pos = finalPos;
	}

	return true;
}


//! returns size of file
long CMemoryReadFile::getSize() const
{
	return Len;
}


//! returns where in the file we are.
long CMemoryReadFile::getPos() const
{
	return Pos;
}


//! returns name of file
const io::path& CMemoryReadFile::getFileName() const
{
	return Filename;
}


CMemoryWriteFile::CMemoryWriteFile(void* memory, long len, const io::path& fileName, bool d)
: Buffer(memory), Len(len), Pos(0), Filename(fileName), deleteMemoryWhenDropped(d)
{
	#ifdef _DEBUG
	setDebugName("CMemoryWriteFile");
	#endif
}


CMemoryWriteFile::~CMemoryWriteFile()
{
	if (deleteMemoryWhenDropped)
		delete [] (c8*)Buffer;
}


//! returns how much was written
size_t CMemoryWriteFile::write(const void* buffer, size_t sizeToWrite)
{
	long amount = (long)sizeToWrite;
	if (Pos + amount > Len)
		amount -= Pos + amount - Len;

	if (amount <= 0)
		return 0;

	c8* p = (c8*)Buffer;
	memcpy(p + Pos, buffer, amount);

	Pos += amount;

	return (size_t)amount;
}



//! changes position in file, returns true if successful
//! if relativeMovement==true, the pos is changed relative to current pos,
//! otherwise from begin of file
bool CMemoryWriteFile::seek(long finalPos, bool relativeMovement)
{
	if (relativeMovement)
	{
		if (Pos + finalPos > Len)
			return false;

		Pos += finalPos;
	}
	else
	{
		if (finalPos > Len)
			return false;

		Pos = finalPos;
	}

	return true;
}


//! returns where in the file we are.
long CMemoryWriteFile::getPos() const
{
	return Pos;
}


//! returns name of file
const io::path& CMemoryWriteFile::getFileName() const
{
	return Filename;
}

bool CMemoryWriteFile::flush()
{
	return true; // no buffering, so nothing to do
}

IReadFile* createMemoryReadFile(const void* memory, long size, const io::path& fileName, bool deleteMemoryWhenDropped)
{
	CMemoryReadFile* file = new CMemoryReadFile(memory, size, fileName, deleteMemoryWhenDropped);
	return file;
}


IWriteFile* createMemoryWriteFile(void* memory, long size, const io::path& fileName, bool deleteMemoryWhenDropped)
{
	CMemoryWriteFile* file = new CMemoryWriteFile(memory, size, fileName, deleteMemoryWhenDropped);
	return file;
}


} // end namespace io
} // end namespace irr

